Imagine a future where discarded coffee grounds could be found in buildings. It seems like something from a children’s storybook.But, truth be told, an interdisciplinary team at the Royal Melbourne Institute of Technology (RMIT) in Australia has shown that fiction is not far from reality.At Melbourne Design Week, the team showcased architectural designs created from locally sourced discarded coffee grounds.A team led by Professor Baohua Jia from RMIT’s School of Science and Nic Bao from the School of Architecture and Urban Design has developed a biodegradable 3D-printing filament that uses coffee waste as its base raw material.By turning coffee waste into 3D-printed architectural forms, the researchers have shown a path toward more sustainable and low-carbon construction materials.Partnership of material scientists and architectsThe work combined expertise from material scientists and architects, bringing coffee closer to a more robust source for biodegradable 3D-printed architectural materials.In the project, the science team helped develop and understand the material. At the same time, the architects suggested computational designs, manufacturing additives, and potential large-scale real-world architectural applications for the new material.“The science team brings deep expertise in developing and understanding the material, while our team explores how the material properties can inform computational design, additive manufacturing, and larger-scale architectural applications,” said Bao.Eco-friendly 3D-printing materialLooking for a more eco-friendly material, researchers in Jia’s lab turned to coffee, which is abundant in their neighborhood and nature-friendly.They noted that much of the leftover grounds were being dumped, so the team examined whether this coffee waste could be repurposed to enhance the design and strength of architectural material.“We use a lot of 3D printing in our work, and that process typically uses a lot of plastics made from cornstarch or less eco-friendly materials,” said Jia. “Given Melbourne is famous for its coffee culture, we thought this could be a good material to investigate.”During their research, one of the team members, Kang Liu, said the project showed that complex forms, which architects often avoid because of high costs, could help improve material performance and function.“With coffee grounds, the material can support sound absorption, insulation, scent, and appearance, giving architects another layer to work with,” said Liu.After the lab research and testing, they moved the project into a full spatial demonstrator, presenting a strong use case of coffee as a viable raw material for biodegradable 3D-printed architectural material.“This provides a tangible example of circular-economy research in action, showing how an everyday waste stream can be converted into a useful material for design, advanced manufacturing and potential future building applications,” she said.Coffee is an important biomaterial that has been engineered with other biological systems to serve as a bio-based raw material. As a medical biomaterial, researchers are combining coffee with other materials to develop antibacterial films, wound-healing dressings, and antioxidant delivery systems. Researchers are also using coffee to make sustainable bioplastics and packaging materials.